Fact-checked by Grok 2 weeks ago

Round goby

The round goby (Neogobius melanostomus) is a small, benthic native to the Ponto-Caspian region of , noted for its aggressive behavior, rapid reproduction, and invasive potential in non-native ecosystems. It features a robust, torpedo-shaped body up to 25 cm in total length, a large head with frog-like eyes and thick lips, fused pelvic fins forming a disk for adhering to substrates, and a characteristic black spot on the first . Coloration varies from yellowish-gray with dark blotches in females and immature males to nearly black in breeding males, which also develop swollen cheeks. This species thrives in shallow, rocky or gravelly bottoms in freshwater and brackish environments, tolerating temperatures from 0–30°C, low oxygen levels, and depths up to 60 m. Originally distributed across the , , , and their tributaries in countries including , , and , the round goby was introduced to via ship ballast water, with the first detection in the (connecting Lakes and Erie) in 1990. It rapidly spread to all five by the mid-1990s and has since established populations in connected river systems, including the lower by 2010, the near by 2018, and inland waterways like the and Rivers with first detections in the in 2021 and ongoing spread as of 2025. In its introduced range, populations can reach densities exceeding 20 individuals per square meter in areas like Calumet Harbor, reflecting its high adaptability and prolific establishment. Ecologically, the round goby is an opportunistic feeder, primarily consuming benthic such as amphipods, chironomid larvae, dreissenid mussels, isopods, and , along with eggs and small vertebrates. Its shifts with and , often favoring mollusks in lentic environments, and its predation can indirectly boost algal growth by reducing grazers. occurs from April to September in multiple spawning events per female, with males aggressively guarding nests containing up to 10,000 eggs that exhibit high fertilization rates; this strategy enables rapid and . The ' tolerance to varied salinities and pollutants further aids its spread. As an invasive species, the round goby poses significant ecological risks by outcompeting native benthic fishes for food and habitat, preying on eggs and fry of species like smallmouth bass, and serving as a vector for contaminants (e.g., heavy metals and PCBs) and diseases such as viral hemorrhagic septicemia and Type E botulism. These impacts have contributed to declines in native fish populations and disruptions in Great Lakes food webs, while economically, it reduces sportfishing opportunities by dominating nearshore areas and consuming bait. Overall, its high invasiveness history and climate suitability score of 0.531 classify it as a high-risk aquatic nuisance species in the United States.

Taxonomy

Classification

The round goby is scientifically classified within the domain Eukarya, kingdom Animalia, phylum Chordata, class , order Gobiiformes, family , subfamily Benthophilinae, genus Neogobius, and species Neogobius melanostomus (Pallas, 1814). This binomial nomenclature reflects its original description by in 1814, based on specimens from the . The species has accumulated several synonyms over time due to taxonomic revisions, including Apollonia melanostoma (, 1814) and Gobius cephalarges (, 1814). These alternative names stem from early classifications that placed the in broader genera before the recognition of more precise phylogenetic groupings. Within the genus Neogobius, which is endemic to the Ponto-Caspian basins, the round goby shares close relations with species such as N. fluviatilis (monkey goby) and N. pallasi (Pallas's goby). The itself derives from (neos, meaning new) and Latin (gobius, referring to gudgeon-like fishes), highlighting its distinct evolutionary lineage among . Phylogenetically, N. melanostomus belongs to the Benthophilinae subfamily, a monophyletic group within that originated in the Ponto-Caspian region and diversified through adaptations for benthic existence in brackish and estuarine waters, including enhanced pelvic fin fusion for substrate adhesion and tolerance to salinity fluctuations. This evolutionary context underscores the subfamily's radiation during the , with Neogobius species exhibiting specialized traits for demersal habitats.

Nomenclature

The scientific name of the round goby is Neogobius melanostomus. The genus name Neogobius derives from "neos," meaning new, combined with "gobius," referring to a gudgeon-like , indicating its status as a newly recognized for certain Ponto-Caspian . The specific epithet "melanostomus" comes from "melas," meaning black, and "stoma," meaning mouth, alluding to the dark coloration inside the mouth. The species was first described scientifically by in 1814 as Gobius melanostomus, based on specimens from brackish waters near in the . It was subsequently transferred to the genus Neogobius, which was established by B. S. Iljin in 1927 to accommodate Ponto-Caspian gobies distinct from other genera. This reclassification was later formalized by L. S. Berg in 1949, who selected Neogobius as the valid genus name among competing proposals. The common English name "round goby" reflects the species' distinctive rounded and its membership in the goby family . In other languages, it is known regionally as "sortmundet kutling" in Danish, "Schwarzmund-Grundel" in , and "babka bycza" in .

Description

Morphology

The round goby (Neogobius melanostomus) exhibits a distinctive characterized by an elongated, tadpole-like form, featuring a large, robust head and a body that tapers gradually toward a narrow , adapted for its benthic . This structure, rounded in cross-section, facilitates maneuverability over substrates in riverine and lacustrine environments. The species lacks a gas , aiding its bottom-dwelling habits. The fins are a key morphological , with the pelvic fins fused into a suctorial that enables the to cling to rocks, , and other surfaces against currents. The first typically bears a prominent black spot at its posterior margin, particularly evident in males, while the second dorsal and anal fins are elongated with soft rays. The head is notably broad and flattened, with prominent, bulging eyes positioned dorsally to provide a wide while on the bottom. The mouth is terminal and large, equipped with thick, fleshy lips, aiding in capturing small and from substrates. The body is covered in ctenoid scales, which are rough and comb-like, distributed across the back, flanks, belly, , and portions of the operculum, providing traction and ; the and top of the head, however, bear smoother scales. The system is complex and well-developed, featuring reduced canals and a high density of superficial neuromasts that enhance mechanosensory detection of prey and predators in low-visibility conditions. Sexual dimorphism is pronounced during the breeding season, with males developing a larger head and enlarged cheeks, as well as thicker first spines, which contribute to territorial displays and nest guarding.

Size and coloration

The round goby (Neogobius melanostomus) typically attains an average total length of 10–25 cm, with a maximum recorded length of 24.6 cm. Weights generally range from 5 to 80 g, though males average larger than females due to . Growth is rapid in the early stages, allowing individuals to reach at 6–8 cm total length. In terms of coloration, the round goby exhibits a mottled pattern of brown to gray with darker spots across the body, while the ventral side remains pale. During the season, males intensify to a blackish hue, with brighter, white-edged median fins.

Native range and habitat

Geographic distribution

The round goby (Neogobius melanostomus) is native to the Ponto-Caspian region of Eurasia, encompassing the basins of the , , , and , as well as their associated freshwater tributaries. This distribution spans coastal and inland waters across parts of and Western , including countries such as , , , , , , , , , and , where the has been established for centuries. Within this native range, the round goby is widespread in the coastal zones of the Ponto-Caspian seas, particularly in brackish and freshwater interfaces. It occurs extensively in major river drainages, including the (flowing into the ), (also basin), and ( basin), where populations thrive in lower reaches and connected waterways. Historically, the species extended into the drainage in , though this range has been influenced by environmental changes in the region. Population densities are notably high in estuaries and river mouths throughout the native basins, where the often dominates benthic assemblages in these productive zones. These areas support large numbers due to favorable conditions for feeding and reproduction, contributing to the species' abundance in the overall native distribution. Historical records of the round goby in its native waters date back to the late 18th and early 19th centuries, with the species first formally described by in 1814 based on specimens from the basin. Documentation from this period confirms its presence in key Ponto-Caspian drainages, establishing a long-term native footprint prior to any recorded expansions.

Habitat preferences

The round goby (Neogobius melanostomus) is , tolerating salinities from 0 to 30 across freshwater, brackish, and marine environments, though it prefers brackish conditions over purely freshwater or fully marine habitats. Optimal growth and performance occur at salinities of 1–15 , with reduced survival and increased stress behaviors evident at levels exceeding 21–24 , particularly under warmer temperatures. As a primarily benthic , the round goby occupies depths from 0 to 30 m, favoring shallow nearshore zones for most activities. It selects substrates offering structural cover, such as rocky bottoms with interstitial spaces, but also inhabits vegetated areas, sandy, or muddy sediments; adults preferentially use rock, while juveniles favor sand. The round goby performs optimally in water temperatures of 15–25°C but demonstrates broad thermal tolerance, surviving from -1°C to 30°C. It exhibits physiological adaptations enabling persistence in hypoxic conditions, thriving at dissolved oxygen levels as low as 0.4–1.3 mg/L and vacating areas only when levels drop below approximately 4 mg/L due to elevated metabolic costs.

Invasive spread

Introduction pathways

The round goby (Neogobius melanostomus), native to the Ponto-Caspian region including the and Seas, was primarily introduced to non-native areas through ballast water discharge from transoceanic ships. This facilitated long-distance transport of larvae and juveniles, with ships taking on in native waters and releasing it in distant ports. The species' first documented introduction to occurred via this mechanism, leading to its detection in the Laurentian . In the , round gobies were first detected in 1990 in the , between and , marking the initial incursion into the region. This event stemmed from shipping routes connecting the Ponto-Caspian area to North American ports, where untreated ballast water served as the conduit. Concurrently, European introductions began in the early 1990s, with the species appearing in the around 1990, specifically in the Gulf of , likely via similar maritime ballast transport from native basins. Further spread in Europe was enabled by the opening of the Danube-Main-Rhine canal system in 1992, which provided an inland waterway corridor linking the drainage to the Rhine River basin and facilitating secondary dispersal. Secondary pathways have contributed to the round goby's subsequent spread within invaded regions. In , canals such as the have allowed upstream and downstream migration, connecting the to inland waterways like the . Additionally, human-mediated overland transport via recreational boats has been implicated, with larvae surviving in water or residual compartments during trailer-based movement between water bodies. Angler activities, including the use of round gobies as live and inadvertent releases of unused baitfish, represent another dispersal route, enabling short- to medium-distance introductions.

Current invasive range

The round goby (Neogobius melanostomus) has established invasive populations across much of the Laurentian Great Lakes basin in North America since its initial detection in the St. Clair River in 1990, spreading to all five Great Lakes and numerous connected waterways by the early 2000s. In recent years, the species has continued to expand into additional systems, including the Hudson River estuary, where it was first documented in 2021 near Troy, New York, with detections extending southward to near Newburgh (river kilometer 92) as of 2025 and potential for further expansion into more brackish areas like the Harlem River based on salinity tolerance studies. Further westward, populations have reached the Mississippi River drainage via connections from the Great Lakes, with detections in the Illinois River as early as the 1990s and a confirmed specimen in Pool 26 of the Mississippi River near Grafton, Illinois, in 2018. In 2025, new detections highlight ongoing range expansion in the , including the first confirmed presence in , , discovered in June near the Bowen Street fishing pier in . This follows earlier incursions into the adjacent Lower Fox River system, where round gobies were identified in Little Lake Butte des Morts above Rapide Croche in 2015, prompting intensified monitoring efforts in 2025 to track spread from urban fishing hotspots. Similarly, in , established populations in and its lower tributaries, such as those in Erie County, have shown signs of upstream movement into inland waterways like the tributaries (e.g., LeBoeuf and French Creeks) by the mid-2020s, with anglers urged to report sightings to prevent further dispersal. In , the round goby is widespread in the , where it became dominant in coastal and estuarine habitats by the early 2000s following introductions via shipping, and continues to expand through maritime traffic as of 2025. The species has also colonized major river systems, including the , where genetic analyses confirm established populations spanning much of the river's length—over 1,000 km from the delta in the upstream into —since the mid-2000s, with the species dominant in catches exceeding 90% in the ; recent genetic studies support invasion via two distinct routes ( corridor and direct maritime).

Biology

Feeding ecology

The round goby (Neogobius melanostomus) is an opportunistic benthic feeder with a diverse diet dominated by sessile and mobile invertebrates, supplemented by fish and their eggs. In invaded North American waters such as the Great Lakes, its primary prey includes mollusks like zebra mussels (Dreissena polymorpha) and native snails. Crustaceans, particularly amphipods (Gammarus spp.), and insect larvae such as chironomids are also key components, especially for smaller gobies, while small fish (e.g., darters and sculpins) and fish eggs contribute to piscivory in adults. This generalist diet reflects high dietary plasticity, allowing adaptation to local prey availability across habitats. As a bottom-dwelling predator, the round goby employs an foraging strategy, using its fused pelvic fins—modified into a powerful disc—to anchor firmly to rocks, mussels, or other substrates while scanning for prey. It detects prey primarily through and chemosensory cues, remaining stationary before lunging with a highly protractile upper to generate for capturing items from the . This method enables efficient predation on attached or slow-moving organisms like bivalves, which are crushed using robust , and is effective both diurnally and nocturnally, with peak feeding activity often at or night. The disc not only facilitates precise positioning but also allows the goby to exploit interstitial spaces in rocky or mussel-covered bottoms, enhancing its competitive edge over . Dietary composition exhibits seasonal shifts tied to prey and life stage, underscoring its opportunistic omnivory. In summer months, mollusks and amphipods dominate as they peak in abundance, while winter diets incorporate more fish and eggs when invertebrate availability declines. Juveniles, in particular, display rapid growth supported by high consumption rates through frequent small meals of planktonic and larval prey like cladocerans and chironomids. Overall, this feeding positions the round goby as a versatile mid-level trophic predator, exerting pressure on benthic communities while integrating into food webs as prey for piscivores.

Reproduction

The round goby (Neogobius melanostomus) exhibits a protracted spawning from to September in its native Ponto-Caspian range, with activity extending into November in warmer invasive habitats such as the Laurentian due to elevated water temperatures. Females are batch spawners capable of producing multiple clutches per , up to six times between water temperatures of 10–11°C and 26°C, with intervals of approximately 3–4 weeks between spawnings. This iteroparous strategy enhances reproductive output in favorable conditions. Fecundity varies with female size, ranging from 100 to 5,000 eggs per , with means around 200–300 eggs in invasive populations and higher values (up to 5,221) reported in native ranges. Fertilization rates can reach 95%, and success is high at 80–95% under guarded conditions, contributing to the species' rapid population establishment. Sexual maturity is attained earlier in invasive ranges than in native habitats. Females typically mature at 1–2 years of age and approximately 6 in total length, while males reach maturity at 2–3 years; in native populations, these ages are delayed by about one year. Semelparity has been suggested for males in some populations, as nest-guarding individuals may cease feeding and exhibit high post-spawning mortality, though this remains unconfirmed across all contexts. Following spawning, adhesive eggs are deposited in single layers within sheltered nests, such as under rocks or in artificial structures. is provided exclusively by males, who guard the clutch, fan the eggs to oxygenate them, and defend against predators, often without feeding for the duration. duration is temperature-dependent, lasting 11–18 days at 20–25°C and up to 36 days at lower temperatures around 12°C, with no viable hatching below 12°C. Upon hatching, larvae measure about 5 mm and enter a brief planktonic stage, undergoing diel vertical migrations—ascending to surface waters at night for feeding and descending during the day—which facilitates passive dispersal via currents before benthic within weeks. This larval dispersal contrasts with the adults' predominantly benthic lifestyle, aiding the species' invasive spread.

Behavior and physiology

The round goby (Neogobius melanostomus) exhibits highly aggressive and territorial behavior, particularly among males, which facilitates interference competition and displacement of . In laboratory observations, resident round gobies displayed significantly more approaches, chases, and bites toward native mottled sculpins (Cottus bairdi) than vice versa, with no aggressive responses from sculpin intruders, indicating the gobies' dominance in resource contests. This territoriality extends to shelter and optimal sites, where round gobies aggressively defend areas, often evicting smaller or less aggressive natives through direct confrontations. Such behaviors contribute to their invasive success by reducing availability for sympatric species. Diel activity patterns in round gobies show peaks in nocturnal and , allowing exploitation of resources under low-light conditions while minimizing during daylight. Juveniles often aggregate in loose schools near substrates, enhancing protection and facilitating initial exploration before adopting more solitary benthic lifestyles. is generally limited in adults due to their lack of a and preference for stable benthic s, with dispersal primarily occurring through larval stages via diel vertical migrations. Larvae rise to surface waters at night, promoting passive by currents and water transport, as observed in collections where no daytime surface captures occurred. Sensory adaptations in round gobies emphasize olfaction for detecting food and mates, supported by 112 genes with expansions in the 7tm1 subfamily, enabling sensitive responses to prey odors and male urinary pheromones that attract females during non-reproductive contexts. They also possess suited to low-light environments, with a RH1 gene for dim-light sensitivity and the ability to distinguish differences even under cataract-induced impairments, aiding benthic at night. Weak fluorescence above the eyes, visible under excitation, may further enhance intraspecific signaling in turbid or low-light waters. Physiological tolerances underpin the round goby's adaptability to varied environments, including high resistance that allows persistence in oxygen-depleted benthic zones, with critical oxygen levels lower than many natives due to efficient oxygen extraction mechanisms. acclimation is robust, with survival and optimal growth at 0–15 over months, ventilation rates minimized near isotonic levels (10–15 ), and no long-term viability above 25 , limiting spread but favoring estuarine invasions. A rapid , evidenced by elevated resting metabolic rates at invasion fronts (up to higher Q10 values across 15–28°C), supports fast somatic growth and energy allocation for competitive behaviors. This metabolic flexibility maintains a broad aerobic scope, enabling thermal compensation from 15–28°C without performance decline.

Ecological impacts

Effects on native species

The round goby (Neogobius melanostomus) exerts significant predatory pressure on native fish species, particularly by consuming eggs and interfering with nesting behaviors. In laboratory experiments simulating stream conditions, round gobies rapidly invaded and seized spawning shelters of mottled sculpins (Cottus bairdii), consuming nearly all eggs within 4–7 days, resulting in egg masses of 0–0.056 g in goby-occupied sections compared to 1.31–4.39 g in control sections without gobies. This predation has led to near-complete recruitment failure for mottled sculpins in affected areas, with no young-of-year observed after the round goby's arrival in Calumet Harbor, southern Lake Michigan, in 1994, and adult populations declining to near extirpation by 1999. Similar effects have been documented across the Great Lakes, where round goby predation on eggs contributes to reduced survival of native benthic fishes, with recruitment reductions approaching 90–100% in localized populations. Competition from round gobies further disadvantages through aggressive territorial behavior and resource overlap. In experimental trials, round gobies displayed significantly higher levels than logperch (Percina caprodes), winning shelter contests in 17 of 24 mixed-species interactions and spending more time in refuges post-intrusion. This enables round gobies to outcompete logperch for benthic habitats and food resources like arthropods, with field observations in showing logperch abundance dropping from 40 individuals per 10 transects in 1995 to 26 in 2001 as round goby numbers surged to 501. Such competitive exclusion has broader implications for native darters and sculpins, which share similar microhabitats and diets, leading to displacement and heightened vulnerability to predation. Round gobies also impact native bivalves by preying on unionid mussels, potentially altering benthic through direct consumption and associated physical damage. Laboratory studies demonstrate that round gobies readily consume juvenile unionids, such as plain pocketbook mussels (Lampsilis cardium), with mortality rates of 9.5–12.1% in goby treatments versus 2.1% in controls, and DNA analysis confirming predation on like the rayed bean (Popenaias popeii) in wild-caught gobies from French Creek, Pennsylvania. This selective predation threatens unionid populations, which rely on stable substrates, and may exacerbate as gobies forage on attached dreissenid mussels, indirectly increasing on unionid shells. Case studies from the Great Lakes illustrate these effects on native fish communities. In southern Lake Michigan's Indiana waters, mottled sculpin trawl catches plummeted from a mean of 0–4.4 fish per hour pre-1998 to effectively zero post-round goby invasion, with frequency of occurrence falling to 0–4%; similarly, johnny darter (Etheostoma nigrum) catches declined from 0–29 fish per hour to 0.17 fish per hour, with occurrence dropping to 15%. In Lake Winnebago, Wisconsin, the 2025 detection of round gobies near the Bowen Street Fishing Pier has raised concerns for walleye (Sander vitreus), as gobies could compete for food and habitat or prey on eggs, potentially disrupting recruitment in this important sport fishery, though monitoring continues to assess emerging impacts.

Role in food webs

In invaded ecosystems such as the , the round goby (Neogobius melanostomus) occupies a significant position as prey, supporting various native predators and facilitating energy transfer within food webs. Sportfish like (Micropterus dolomieu) and (Perca flavescens) readily consume round gobies, with the latter comprising up to 75% of smallmouth bass diets in and contributing to post-invasion increases in bass mass by approximately 17% for individuals around 6 inches in length. Yellow perch incorporate round gobies at frequencies of about 22% in their diets within certain fluvial habitats of the system, enhancing their nutritional intake from this abundant resource. Avian predators, including double-crested cormorants (Phalacrocorax auritus), have shifted to rely heavily on round gobies, which now form a dominant component of their diets in eastern and other areas, buffering predation pressure on native prey fish. Reptilian predators, such as the (Nerodia sipedon insularum), have experienced a population surge due to this prey availability, with round gobies constituting over 90% of their consumed biomass; this has driven watersnake numbers from fewer than 2,000 adults in 1999 to around 12,000 by 2011. As a mid-level benthic predator in its native Ponto-Caspian range, the round goby primarily targets invertebrates like and small mollusks. However, in invasive contexts, larger individuals (>100 mm) shift toward consuming dreissenid mussels (Dreissena spp.), elevating their effective trophic position and creating a novel linkage between primary benthic producers and higher-level consumers. This mussel reliance allows round gobies to channel from the to piscivores, as evidenced in central where they process substantial —older gobies consume over 80% dreissenids by weight—altering traditional energy flows from pelagic to more benthically dominated pathways. The proliferation of round gobies has boosted overall fish in several basins, with standing stocks in estimated at 203–4,803 tonnes and annual accumulations reaching 475–8,943 tonnes during peak invasion years around 1999. This abundance supports enhanced growth and condition in predators, such as exhibiting 12% greater mass in larger size classes post-invasion in , though it simultaneously reshapes trophic dynamics by concentrating energy in invasive pathways rather than native ones.

Management and control

Prevention strategies

Prevention of further spread of the round goby (Neogobius melanostomus) primarily focuses on interrupting known introduction pathways, particularly through maritime and recreational activities in . Ballast water management represents a of prevention efforts, as transoceanic shipping introduced the species to the in the early 1990s. Regulations under the International Maritime Organization's () Ballast Water Management Convention, which entered into force on September 8, 2017, mandate ballast water exchange or treatment to minimize viable organisms in discharged water, building on earlier guidelines from 1997. In the , the U.S. has enforced stringent requirements since 2012 for vessels entering from outside the , including open-ocean exchange or approved treatment systems, effectively curbing new transoceanic introductions. These measures, combined with no-discharge zones, have significantly reduced the risk of additional Ponto-Caspian species like the round goby arriving via . Boater education campaigns emphasize preventing overland transport by recreational watercraft, a key vector for secondary spread within inland waterways. The "Clean, Drain, Dry" protocol, promoted by the U.S. Fish and Wildlife Service's Stop Aquatic Hitchhikers! program and adopted across U.S. and Canadian Great Lakes states, instructs boaters to remove visible plants and animals, drain all water from bilges, live wells, and engines, and dry equipment for at least five days before launching elsewhere. In New York, for instance, the Department of Environmental Conservation integrates this into round goby-specific outreach, including boat steward inspections at high-risk launch sites to demonstrate decontamination steps. Similar initiatives in Michigan and Ontario target anglers and marinas, reducing hitchhiker transfer by up to 90% when followed. Regulations prohibiting the use of live round gobies as bait address angler-mediated dispersal, which has facilitated range expansion into tributaries and disconnected waterbodies. All states, including , , , and , ban possession, transport, and use of live round gobies, with prohibitions enacted as early as 2005 in under invasive species laws and extended regionally by 2010. In , for example, moving round gobies is illegal, and anglers must kill and report any caught outside established areas to prevent intentional or accidental releases. These rules, enforced through fishing licenses and checkpoints, have limited trade as a vector, though compliance relies on public awareness. Early detection monitoring programs enable rapid response to potential new introductions, using a combination of environmental DNA (eDNA) sampling and citizen science. eDNA techniques, which detect species-specific genetic material in water, have proven effective for non-invasive surveillance; in the Great Lakes, quantitative PCR assays identify round goby presence at low densities, with studies in Lakes Huron and Michigan confirming detections alongside traditional trawling. In Pennsylvania, the iMapInvasives platform integrates eDNA "hits" from ongoing studies to map expansion risks and guide targeted surveys. Complementing this, angler reporting programs, such as Pennsylvania's 2025 initiative launched in October, solicit input from northwest anglers via workshops and online tools to track sightings in Lake Erie tributaries like French Creek, informing education and containment strategies. These efforts, coordinated by state agencies and USGS databases, facilitate early intervention before populations establish.

Eradication and mitigation

Efforts to eradicate or mitigate round goby populations focus on established invasions, where complete removal is challenging due to the ' high reproductive rates and habitat preferences. Chemical controls, such as piscicides, have been tested for targeted application, with round gobies showing sensitivity to compounds like comparable to many native fish , limiting their selectivity in larger water bodies. Pheromone-based traps have also been trialed experimentally. Acoustic playback traps, mimicking round goby reproductive calls, have shown promise in improving capture efficiency and selectivity over traditional food-baited methods in controlled studies. Biological mitigation strategies emphasize leveraging natural ecosystem processes and human intervention to suppress populations. Promoting native predators, such as piscivorous , has been explored as a biocontrol mechanism, with research indicating that enhanced predation pressure and can limit round goby spread in coastal and riverine habitats. In the , 2025 European Union initiatives under the RoundGoby project have promoted "eat the invader" campaigns, encouraging and consumption of round gobies through product development like canned goods, , and public cooking challenges to reduce densities while creating economic opportunities. These efforts aim to transform the species from a into a , though sterile mate releases remain conceptual for round gobies, drawing from broader invasive control precedents without species-specific implementation to date. Physical removal methods, including , netting, and , are commonly applied in localized areas to reduce densities. In the 2025 Lake Winnebago response, as of November 7, Wisconsin Department of Natural Resources crews used backpack , , and traps, capturing over 50 individuals, with early efforts yielding at least nine verified specimens near the pier to curb establishment. Intensive programs, such as baited trap deployments in the , have demonstrated effectiveness in site-specific reductions, with a 2024 study reporting a 67% decline in capture rates within targeted zones compared to untreated references. Emerging genetic tools offer potential for long-term control, building on the 2020 round goby sequencing that enables targeted manipulations, though practical applications like induction via remain in early research stages without field deployment by 2025. Overall success in eradication is limited, with experts noting that once established, round goby populations are nearly impossible to fully eliminate due to their resilience and rapid colonization. Mitigation efforts have achieved partial density reductions of up to 67% in confined areas through intensive physical removal, providing localized relief for but requiring sustained monitoring to prevent rebound.

Parasites and pathogens

Native parasites

In its native range within the Ponto-Caspian basin, including the Black Sea and Caspian Sea, the round goby (Neogobius melanostomus) harbors a diverse parasite community comprising over 70 metazoan species. Trematodes dominate this assemblage, with notable examples including Cryptocotyle lingua and Cryptocotyle concava, while cestodes such as Cyathocephalus truncatus and nematodes like Philometra sp. also contribute significantly to the parasite fauna. This richness reflects the gobies' role in complex aquatic ecosystems where multiple host-parasite interactions occur. Prevalence of is notably high in native populations, with co-infections involving multiple parasite taxa being commonplace. Infection intensities vary by location and age, though some trematode exhibit higher burdens. Many of these parasites, particularly trematodes, utilize round gobies as in their life cycles, facilitating to definitive hosts such as piscivorous or larger through predation. In comparison to these native assemblages, round gobies in invasive ranges generally experience substantially reduced parasite loads.

Invasive range parasites

In the invasive range of the round goby (Neogobius melanostomus), particularly in the , approximately 22 metazoan parasite species have been documented, a substantially lower diversity compared to the 72 species reported from its native range. Trematodes represent the most prevalent group among these, with the Diplostomum spathaceum commonly infecting the eyes of round gobies across multiple localities. This reduced parasite diversity and abundance align with the enemy release hypothesis, which posits that experience diminished parasitic regulation in novel environments, facilitating population expansion. Parasite prevalence in round gobies remains low, typically ranging from 10% to 30% for most taxa, with many infections involving immature stages and rare adult forms, contrasting with higher loads in co-occurring native fish . No significant increase in overall has been observed over a decade following establishment, underscoring sustained enemy release. As of 2022, studies in the show juvenile round gobies acquiring local parasites seasonally, but overall burdens remain low. Some parasites native to the invasive range have been transmitted to round gobies through shared intermediate s, enabling co-infections. For instance, the Anguillicoloides crassus, an invasive parasite primarily affecting s, has been found encapsulated within cysts of the acanthocephalan Pomphorhynchus laevis in round gobies, with larvae present in 12% of examined cysts, serving as a paratenic that facilitates to definitive s via predation. While parasite loads exert minimal health impacts on round gobies, allowing high population densities, there is potential for spillover to sharing habitats and prey resources. Recent studies indicate that round gobies can act as reservoirs for parasites such as trematodes in sympatric natives, though some evidence suggests a dilution effect reducing infections in certain following goby invasions. In the , another key invasive range, surveys have revealed 24 native parasite infecting round gobies, including , trematodes, cestodes, nematodes, and acanthocephalans, with overall around 78%. These findings reflect an increasing parasite over time, as earlier assessments in the region documented only 4–12 shortly after , suggesting gradual accumulation of local parasites.

References

  1. [1]
    [PDF] Neogobius melanostomus (Round Goby) Ecological Risk Screening ...
    The Round Goby is native to Eurasia, including the Black Sea, Caspian Sea, and Sea of Azov. It has spread to all five Great Lakes and the lower Illinois River.
  2. [2]
    [PDF] Round Goby Aquatic Invasive Species factsheet
    The round goby is a small, but aggressive bottom-dwelling fish that grows rapidly and reproduces several times in one spawning season.
  3. [3]
    Round Goby Fact Sheet - Pennsylvania Sea Grant
    Jul 21, 2025 · The Round Goby is a small, but aggressive bottom-dwelling fish that grows rapidly and reproduces several times in one spawning season.<|control11|><|separator|>
  4. [4]
  5. [5]
    [PDF] a review of round goby Neogobius melanostomus biology, spread ...
    The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian ...
  6. [6]
  7. [7]
    Escape from the Ponto-Caspian: Evolution and biogeography of an ...
    Aug 5, 2025 · Results of all phylogenetic approaches are highly congruent and provide very strong support for recognizing the subfamily Benthophilinae; which ...Missing: context | Show results with:context
  8. [8]
    Evolution of microhabitat association and morphology in a diverse ...
    Neogobiines in the subfamily Benthophilinae (Ponto-Caspian & Mediterranean lineage of Thacker and Roje (2011)) achieved remarkable diversity via a shift from ...Missing: context | Show results with:context
  9. [9]
    Neogobius melanostomus (Pallas, 1814) - GBIF
    Etymology: Greek, melanos = black + Greek, stoma = mouth, means black-mouthed, but might be thought to refer to the conspicuous black spot typically present on ...
  10. [10]
    Neogobius melanostomus (Pallas, 1814) - WoRMS
    To FishBase (from synonym Neogobius melanostomus affinis (Eichwald, 1831)) To FishBase (from synonym Neogobius cephalarges cephalarges (Pallas, 1814)) To ...
  11. [11]
    World Register of Marine Species - Neogobius Iljin, 1927 - WoRMS
    Neogobius Iljin, 1927 ; Animalia (Kingdom) ; Chordata (Phylum) ; Vertebrata (Subphylum) ; Gnathostomata (Infraphylum) ; Osteichthyes (Parvphylum) ...
  12. [12]
    CAS - Eschmeyer's Catalog of Fishes
    Berg 1949 is regarded by Miller & Vasil'eva 2003:163 [ref. 27344] as the first reviser, selecting Neogobius over other new names described by Iljin 1927.
  13. [13]
    Neogobius melanostomus (round goby) | CABI Compendium
    The subfamily Goibionellinae (Nelson, 1994), was previously labelled Benthophilinae. ... Spread of alien (non-indigenous) fish species Neogobius melanostomus in ...
  14. [14]
    Round goby (Neogobius melanostomus) - Minnesota DNR
    The round goby is a small, aggressive bottom-dwelling fish. They usually grow three to six inches long, but can grow up to ten inches.Missing: family genus synonyms
  15. [15]
    round goby - Illinois Department of Natural Resources
    The round goby has a large head with eyes placed high on the head. Its tapered body has pelvic fins joined to form a sucker The second dorsal fin and the and ...Missing: anatomical scales
  16. [16]
    Neogobius melanostomus, Round goby - FishBase
    Neogobius melanostomus (Pallas, 1814) · Classification / Names Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa.Missing: scientific family
  17. [17]
    Neogobius melanostomus (Gobie arrondie) - Animal Diversity Web
    Rebecca Hayes (author), University of Michigan-Ann Arbor, Phil Myers ... "fishbase.org" (On-line). Accessed December 10, 2008 at http://www.fishbase ...<|control11|><|separator|>
  18. [18]
    Organization and Ontogeny of a Complex Lateral Line System in a ...
    Dec 18, 2020 · Gobies (family Gobiidae) have a complex mechanosensory lateral line system characterized by reduced lateral line canals and a dramatic proliferation of small ...
  19. [19]
    Evidence for ontogenetically and morphologically distinct alternative ...
    Apr 3, 2017 · Evidence for ontogenetically and morphologically distinct alternative reproductive tactics in the invasive Round Goby Neogobius melanostomus.
  20. [20]
  21. [21]
    Round goby - Facts, Diet, Habitat & Pictures on Animalia.bio
    The round goby (Neogobius melanostomus) is a euryhaline bottom-dwelling species of fish of the family Gobiidae. It is native to Central Eurasia, ...
  22. [22]
  23. [23]
    Round Goby - Montana Field Guide
    The round goby is a small, invasive fish with fused pelvic fins, not found in Montana, and is not native to the US.
  24. [24]
    Round Goby - National Invasive Species Information Center (NISIC)
    The round goby (Neogobius melanostomus) is native to the Black and Caspian Seas between Europe and Asia and was brought to the U.S. by way of the Great Lakes in ...Missing: biology | Show results with:biology
  25. [25]
  26. [26]
    [PDF] ROUND GOBY - Lake Champlain Basin Program
    The round goby was first detected in 1990 into the St. Clair River, where several collections were made on both the U.S. and the. Canadian sides of the ...
  27. [27]
    Monitoring Round Goby (Neogobius melanostomus) Population ...
    In the Great Lakes basin, round gobies (Neogobius melanostomus) were first reported from the St. Clair River in 1990. Reported here are the details of range ...
  28. [28]
    The round goby (Neogobius melanostomus) in the Gulf of Gdańsk
    The first record of this fish in the Baltic Sea is from 1990. Early detection of the invader enabled the study of population growth and changes in the area.
  29. [29]
    [PDF] The round goby (Neogobius melanostomus) - INBO
    Oct 21, 2019 · The round goby reached the Baltic Sea by the Gulf of Gdansk (Poland) in 1990 and the German part of this sea in 2002 (Kottelat and Freyhof, ...
  30. [30]
    Round Goby - NYSDEC
    Round goby (Neogobius melanostomus) is a highly invasive bottom-dwelling fish from the freshwater region of Europe's Black and Caspian Seas. They have voracious ...Missing: family genus synonyms
  31. [31]
    [PDF] Invasive goby larvae: first evidence as stowaways in small watercraft ...
    Dec 12, 2021 · Recreational boats were active after sunset throughout the reproductive season of invasive gobies and are therefore a realistic translocation.
  32. [32]
    [PDF] Round Goby (Neogobius melanostomus)
    A transfer of contaminants to upper trophic levels by round goby may cause human health issues when the contaminated fish are eaten frequently. • Impacts are ...
  33. [33]
    Round goby - Vander Zanden Lab - University of Wisconsin–Madison
    (Neogobius melanostomus) ... The round goby is a globally invasive fish, with extensive introduced populations in the Laurentian Great Lakes watershed, the Baltic ...Missing: etymology | Show results with:etymology
  34. [34]
    Invasive gobies in the Hudson River
    Aug 31, 2021 · The round goby is a small fish from southeastern Europe that was carried into the Great Lakes in untreated ballast water of an ocean-going ship.
  35. [35]
    Invasive Round goby Neogobius melanostomus distribution, relative ...
    Jan 12, 2024 · The Round goby (Neogobius melanostomus) is a small, benthic fish native to Europe's Black and Caspian seas that is widely recognized as a ...
  36. [36]
    Invasive round gobies discovered in 2025 in Lake Winnebago
    Sep 26, 2025 · The round goby is an aquatic invasive species. It can displace native fish populations and has the potential to impact Lake Winnebago's sport ...Missing: range | Show results with:range
  37. [37]
    Reminder - Report Catches of Round Goby in Winnebago System
    Jul 21, 2025 · Round gobies are an invasive species that range in size from 3 to 6 inches and have a blotchy gray appearance. They can be identified by a ...
  38. [38]
    Dealing with the invasive round goby species in the Baltic Sea region
    Feb 5, 2025 · Originating from the Black Sea, the round goby is a highly invasive fish in the Baltic Sea, arrived mainly through maritime and inland shipping.
  39. [39]
    Round gobies (Neogobius melanostomus) in the River Rhine
    Sep 19, 2024 · The round goby, Neogobius melanostomus, is a successful invasive fish species. Originating from the Caspian and Black Sea, it is now distributed widely within ...
  40. [40]
    Invasion strategies in round goby (Neogobius melanostomus)
    We studied the invasion performance of one of the most invasive species worldwide, the round goby Neogobius melanostomus, from total absence over first ...Missing: pathways baitfish
  41. [41]
    Diel diet composition and feeding activity of round goby in the ...
    We examined the diets of 300 round gobies collected during crepuscular, diurnal, and nocturnal periods in Lake Ontario. There was little variation in the diel ...Missing: papers | Show results with:papers
  42. [42]
    Diet and feeding strategies of round goby, Neogobius ...
    The results show that the round goby consume a wide range of different organisms – 76 taxa in total (identified to family, genus or species level).
  43. [43]
    Habitat utilization and feeding ecology of small round goby in a ...
    Sep 21, 2020 · Although first records of this species at the German coast of the Baltic Sea date back to 1998 (Winkler 2006), in our study area, round gobies ...
  44. [44]
    (PDF) Seasonal abundance, diet, and energy consumption of round ...
    PDF | Pennuto CM, Krakowiak PJ, Janik CE. Seasonal abundance, diet, and energy consumption of round gobies (Neogobius melanostomus) in Lake Erie.
  45. [45]
    Round goby (Neogobius melanostomus) δ13C/δ15N discrimination ...
    Apr 24, 2023 · Diets changed as round gobies grew, with small round gobies (17-42mm) feeding mostly on cladocera and chironomids, intermediate sized gobies (43 ...
  46. [46]
    Full article: Predator and prey: the role of the round goby Neogobius ...
    In the Baltic Sea, round gobies were first caught in the Gulf of Gdansk in 1990 (Skóra & Stolarski 1993, 1996) and had become one of the dominant species in ...
  47. [47]
    RNA sequencing of early round goby embryos reveals that maternal ...
    Mar 22, 2018 · Round goby females can spawn up to six times per summer once the water temperature reaches 10–11 °C, but in the sampled population, two to ...Missing: care | Show results with:care
  48. [48]
  49. [49]
    Reproduction of the round goby (Neogobius melanostomus) under ...
    Aug 6, 2025 · For natural spawning, the period from spawning to hatching was 18-19 days, at a constant temperature of 20°C. Genitourinary papilla of the ...
  50. [50]
    [PDF] The effect of temperature on round goby (Neogobius melanostomus ...
    No viable hatch was observed in temperatures below 12°C. The development time of embryos varied from 36 days in water at 12°C to 11 days in water at 25°C. This ...
  51. [51]
    Diel Vertical Migration of Round Goby Larvae in the Great Lakes
    We suggest vertical migration behavior may have allowed larval round gobies to be transported to and within the Great Lakes via ballast water and dispersed in ...
  52. [52]
    Diel Vertical Migration of Round Goby Larvae in the Great Lakes
    Aug 7, 2025 · Although round goby are benthic and have no strictly pelagic larval phase, round goby larvae have been sampled nocturnally in the pelagic zones ...
  53. [53]
    Behavioral Interactions Between Round Gobies (Neogobius ...
    We examined territorial behaviors and interactions between two species of benthic clingers, nonindigenous round gobies (Neogobius melanostomus) and native ...
  54. [54]
    Dominance hierarchy establishment in the invasive round goby ...
    Round Goby are benthic fish that utilize rocky shelters for predator avoidance and as reproductive sites in which territorial males defend clutches of eggs.Missing: territoriality | Show results with:territoriality
  55. [55]
    Habitat Matters: Behavior and Activity of Round Goby (Neogobius ...
    The Round Goby (Neogobius melanostomus) is an alien species, first recorded in the Baltic Sea in 1990 [3]. ... Habitat Matters: Behavior and Activity of Round ...<|control11|><|separator|>
  56. [56]
    Diel Vertical Migration of Round Goby Larvae in the Great Lakes
    We suggest vertical migration behavior may have allowed larval round gobies to be transported to and within the Great Lakes via ballast water and dispersed in ...Missing: schooling | Show results with:schooling
  57. [57]
    The round goby genome provides insights into mechanisms that ...
    Jan 28, 2020 · We find that the round goby genome contains the usual complement of PRC2 components: two copies of SUZ12 (of which one appears quite diverged), ...Missing: thicker spine breeding
  58. [58]
    Consequences of eye fluke infection on anti-predator behaviours in ...
    Apr 6, 2017 · Our results demonstrate that round gobies with intense cataract could assess the present light intensity differences, including a relatively low ...
  59. [59]
    [PDF] Noel Schmitz_Thesis_FINAL - OhioLINK ETD Center
    Round Goby tolerate hypoxic conditions (i.e. critical lethal threshold range of 0.4-1.3 mg/L) and are able to withstand temperatures ranging from –1 to 30°C. ( ...<|control11|><|separator|>
  60. [60]
    Salinity tolerance of the invasive round goby - ScienceDirect.com
    Here, our more comprehensive experimental regime evaluated short and long-term abilities of the round goby to survive and acclimate in various salinities.Missing: hypoxia | Show results with:hypoxia
  61. [61]
    boldness, dispersal tendency, and metabolism at the invasion front
    Apr 27, 2015 · In conclusion, our results reveal that the round goby from an invasion front are bolder, have higher dispersal potential, and higher metabolic ...
  62. [62]
    Effects of temperature on physiological performance and behavioral ...
    We show that round goby maintained a high aerobic scope from 15 to 28°C; that is, the capacity to increase its aerobic metabolic rate above that of its ...
  63. [63]
    [PDF] Status and Strategy for Round Goby Management - State of Michigan
    The invasion of round goby (Neogobius melanostomus), native to the Black Sea, threatens the waters of the State of Michigan. The goals of this document are ...
  64. [64]
    Implementing the Ballast Water Management Convention
    The BWM Convention entered into force globally on 8 September 2017. Which ships does the convention apply to? The convention applies to ships registered under ...
  65. [65]
    [PDF] Ballast Water Management for Vessels Entering the Great Lakes
    May 17, 2013 · SUMMARY: The Coast Guard is issuing regulations to require Ballast Water. Management practices for each vessel entering the Great Lakes After ...
  66. [66]
    DEC and Canal Corporation Announce Comprehensive Effort to ...
    Mar 24, 2022 · ... Clean, Drain, Dry" campaign. Boat stewards demonstrate how to conduct boat and trailer inspections prior to launching into a new waterbody ...
  67. [67]
    0280: ANALYSIS AS ENACTED (6-29-09) - INVASIVE SPECIES
    Jun 29, 2009 · In an effort to control invasive species in Michigan, legislation was enacted in 2005 to prohibit a person from possessing certain plant, fish, ...
  68. [68]
    Help wanted: Stop the spread of invasive round goby fish in Pa.
    Oct 31, 2025 · It releases species like round goby and zebra mussels. Round goby are very good at adapting. They were introduced in the 1990s and have ...
  69. [69]
    Round Goby Detection in Lakes Huron and Michigan—An ... - MDPI
    We collected eDNA from water samples alongside bottom trawls and hook and line angling in Lakes Huron and Michigan to detect round goby.
  70. [70]
    Tracking Invasive Species with Pennsylvania iMapInvasives
    Mar 21, 2023 · eDNA to Monitor Round Gobies ... The objectives of this on-going study are to use "hits" - positive findings of round goby eDNA - to help ...
  71. [71]
    Angler Input Needed to Help Stop the Spread of Invasive Round Goby
    Oct 17, 2025 · Growing concerns that the Round Goby will spread to additional inland waterways, particularly those adjacent to Lake Erie, have inspired ...
  72. [72]
    [PDF] Parasite infection of the non-indigenous round goby (Neogobius ...
    Nov 4, 2019 · In its native range in the Black Sea and Sea of Azov, a total of 71 and 43 parasite species, respectively, have been recorded in the round goby.
  73. [73]
    Checklist of parasites for Ponto‐Caspian gobies (Actinopterygii ...
    Apr 11, 2020 · This study provides a comprehensive checklist of parasites reported for native and non-native populations of seven Ponto-Caspian goby species.
  74. [74]
    Parasites of the round goby, Neogobus melanostomus (Pallas, 1811 ...
    Aug 10, 2025 · This study describes the parasites of the round goby in its new environment. In 2004, 486 round goby specimens from the Vistula Lagoon were ...
  75. [75]
    Metazoan Parasites of Introduced Round and Tubenose Gobies in ...
    Trematodes are the most common parasitic group of the round goby in the Great Lakes, as in their native Black Sea range and Baltic Sea introduction. Holarctic ...
  76. [76]
    Invasive species are less parasitized than native competitors, but for ...
    Jun 20, 2025 · Round gobies from each of 3 sampled localities were also less heavily infected than both indigenous species. This is in contrast to what is ...
  77. [77]
    First evidence for a possible invasional meltdown among invasive ...
    Oct 10, 2018 · crassus might use the cyst as a “hideout” to evade the immune response of the round goby, which might serve as prey for A. anguilla, the ...
  78. [78]
    Helminth Parasites of Invasive Freshwater Fish in Lithuania - PMC
    In this paper, we studied the parasitic worms of invasive fish in Lithuania. We focused on four fish species foreign to Lithuanian freshwaters.
  79. [79]
    [PDF] Reduced survival of a native parasite in the invasive round goby
    Feb 15, 2016 · Here we evaluate the relative host competence of the invasive round goby (Neogobius melanostomus) for a native acanthocephalan species, ...Missing: cestodes | Show results with:cestodes